6. Wait a day and then ask him, “What did you do yesterday?”
“If he lies to me then, I’ll tell him the truth: ‘I saw you yesterday.’” This approach involves you directly questioning your boyfriend and not beating around the bush. When asking this kind of question, start off by talking about what you did and making some small talk first to make the question seem more natural. This allows you to corner him so he can’t deny it; then you can find out the truth.